/** 初始化全局样式 */
*{
  margin: 0px
  padding: 0
}
html,body{
  width: 100%
  height: 100%
}
ul{
  list-style:none
}
a{
  text-decoration: none
} 
img{
  vertical-align: top
  border: none
}

.clearf:after, .clearf:before{
  content: ""
  display: block
  clear: both
}
